Neural tube defects are one of the most common birth defects, affecting ~5 in 10,000 pregnancies in the US and Europe. This congenital malformation is influenced by environmental and genetic factors. NTDs occur when the neural tube fails to close completely usually before day 21 of human fetal development. Depending on the site, the subsequent development of the brain and/or spinal cord is affected. About a third of NTDs consist of anencephaly, a failure of the brain to develop, resulting in death within a few hours of birth. The majority of the remaining NTDs consist of myleomeningocele, commonly called spina bifida. This involves vulnerability of the developing spinal cord with a wide spectrum of severity that can require lifelong care. The most established risk for developing NTDs is low maternal folate levels. Periconceptual folic acid supplementation in mothers reduces the risk of an NTD pregnancy by 50-70%. This project is designed to understand the role of genetics in NTD by carrying out a genome wide association study. This type of study requires scanning the entire genome using a specialized genetic testing chip. We have collected DNA from more that 5,000 individuals participating in studies designed to understand the genetics of NTDs. Participants include patients, their parents and unaffected individuals who will serve as control.